This year’s Senate race between Kamala Harris and Loretta Sanchez – two Democrats – has raised some eyebrows about our state’s top-two primary system. Some have questioned the prudence of pitting two Democrats against each other in November.

How quickly the critics forget.

When Californians came together to fix our broken election system in 2010, our politics were a mess. Pew Charitable Trust gave California the lowest grade in the nation for performance, and the National Journal rated us among the most dysfunctional state governments. We proved them both right by breaking the record in 2010 for consecutive days without a state budget. No wonder our legislature had a 14 percent approval rating.

Californians voted to overhaul our system in 2010 because we wanted the same innovation in our government that has made our state’s private sector the envy of the world. Enacting top-two open primaries and nonpartisan redistricting has been a success. Voter turnout is up. Partisan warfare is down. We are no longer a national symbol of political failure.

The move to top-two primaries empowered more than 5 million independent and minor party voters (more than the number of registered Republicans). They now have full access to every round of voting.

While much of the country is stuck in a 40 year low of electoral competitiveness, California elections are now the most competitive in the nation. Before we reformed the system, 80 percent of state legislative elections were uncompetitive. Today more than half of all races are competitive, and winning does not mean you have a job for life. Compare that to Virginia, which uses a partisan primary system and has a 100 percent legislative incumbency rate.

Minority representation has also grown. African-American representation has increased 50 percent in the Legislature. Latino candidates for state office have jumped 27 percent and Latino candidates for Congress have jumped 118 percent. The California Hispanic Congressional delegation has grown 50 percent since top-two’s adoption.

The atmosphere in Sacramento has changed. Partisan gamesmanship for political advantage has become far less prevalent, and bipartisan coalitions have formed to address previously intractable issues.

This year California had one of the most productive legislative sessions in our history. Liberals and conservatives, business and labor hammered out major reforms from a minimum wage increase to the battle against climate change.

And, as a sign of real progress, the Legislature passed and the governor signed a very significant package of gun safety bills. As a result of working together, the Legislature’s approval rating has climbed from 14 percent to 42 percent.

Which brings me back to the Harris-Sanchez race.

Thirty-four candidates faced off in the primary. More than 7 million Californians (41 percent of registered voters) voted, placing California in the top ranks of voter turnout. Independent voters and independent candidates were able to fully participate in the first round.

And don’t believe the critics who say that two Democrats advancing to the finals is proof that open primaries don’t work. Kamala Harris is now going to Washington with a mandate to represent all Californians, not just Democrats. She will have the capacity to vote independently and challenge her party’s leadership.

We’ve seen this independence from members of the California Republican Congressional delegation, many of whom stood up to Republican leadership and voted against the government shutdown in 2013.

Six years ago, Californians had the foresight to take our primary elections out of the hands of the political parties and demand better. The results have been transformational. We are thriving, and concerned citizens from Florida to Alaska are exploring how to bring the “California model” of nonpartisan redistricting and open primaries to their states.

There’s no looking back.

Steve Westly runs a large sustainability venture capital firm and was California controller from 2003 to 2007. He wrote this for The Mercury News.